Recording and reproducing mechanism



1937- T. J. MOLLOI' RECORDING AND REPRODUCING MECHANISM Filed Nov. 23,1936 4 Sheets-Sheet l INVENTOR Tom BY J No Hay.

ATTOR Y Au 10, 1937. -r. J. MOLLOY RECORDING AND REPRODUCING MECHANISMFiled Nov. 23, 1936 4 Sheets-Sheet 2 Rx i INVENTQR Tom J Mo flay BYATTOR EY Aug. 10, 1937. T. J. MOLLOY RECORDING AND REPRODUCING MECHANISM4 Shets-Sheet .5

Filed Nov. 2:, 1936 INVENTOR 72202 J Mafia u ATTORNEY Aug. 10, 1937. 'r.J. MOLLOY RECORDING AND REX RODUCING MECHANISM Filed Nov. 23, 1936 4Sheets-Sheet 4 \m 3 NM N km N Ill I A. II R INVENTQR T007 J Mo/lo BY"77!! K I ORNEY Patented Aug. 10, 1937 UNITED STATES PATENT OFFICERECORDING AND REPRODUCIN G MEG HANIS 21' Claim.

This invention relates to sound recording and reproducing apparatus andparticularly to a telegraph-phone wherein translated sound vibrations,in the form of electrical current impulses, are passed through amagnetic circuit to effect magnetization of a continuously movingmagnetizable element, such as a steel strand or ribbon, and whereinsubsequent reproduction is offected by causing the magnetized record toinduce fluctuating electrical impulses which may be translated toproduce the original sound vibrations. Apparatus of this character hasnot come into commercial use because of failure to successfully respondto the wide range of frequencies required for satisfactorily reproducingboth speech and musical renditions, particularly the latter whichrequires handling of most of the audible spectrum for good soundreproduction. Extremely long length of record and high speed operationnecessary to produce a given recording, together with excessivedisturbances caused by vibration of the record, have added to otherinherent defects which make such systems of recording undesirable.

It is. therefore, the principal object of the present invention toovercome the above defects and to provide an apparatus of this characterwhich will produce records from which sounds or signals are producedwith greater degree of fidelity and naturalness.

Other important objects of the invention are to provide an electromagnetwherein the e fective field thereof is confined to a limited extent; toprovide for recording higher frequency ranges by registering each cyclewithin a limited area on the record; to provide a recording apparatuswherein the required length of the record is reduced to a minimum inproportion to the length of time required in making a recording; toprovide an apparatus wherein the reproduction of background noises areminimized; and to provide support for the record whereby vibration iseliminated without subjecting the record to undue wear and which doesnot interfere with splices or repairs made in the record as in the caseof breakage.

In accomplishing these and other objects of the invention, ashereinafter pointed out, I have provided improved details of structure,the preferred form of which is illustrated in the accompanying drawings,wherein:

Fig. 1 is a perspective view of an apparatus constructed in accordancewith the present invention for recording and reproducing translatedsound vibrations.

Fig. 2 is a perspective view of the apparatus as viewed from the rear,particularly illustrating the drive and control mechanisms for effectingmovement of the record across the effective field of the magnet.

Fig. 3 is a cross-section through the apparatus on the line 33 of Fig.2.

Fig. 4 is a detail perspective view of the magnet and its support thatis used in subjecting the record to a polarizing flux and clearing it ofprevious magnetization, thereby permitting reuse of the record elementin making a new recording.

Fig. 5 is a detail perspective view of one of the record-storing reelsand its supporting shaft, particularly illustrating the drivingconnection therebetween.

Fig. 6 is a detail perspective view of the record driving pulley wherebyconstant uniform pull is imparted to the record while it is being drawnacross the influencing point of the magnet.

Fig. 7 is a detail perspective view of the record guide arm foruniformly locating the lays of record across the width of the windingreel.

Fig. 8 is an enlarged detail section through the electromagnet and guideacross which the record is drawn incidental to recording or reproducingsounds and signals.

Fig. 9 is a cross-section through the electromagnet on the line 99ofFig. 8.

Fig. 10 is a detail perspective view of the magnet shield particularlyillustrating the gap through which the point of the magnet projects intoinfluencing relation with the record.

Fig. 11 is a detail perspective view of the parts of the electromagnetcore and the magnetic point used in -imparting magnetism to and from therecord.

Fig. 12 is a detail section on the line l2l2 of Fig. 1.

Referring more in detail to the drawings:

I designates a casing for enclosing a sound reproducing and recordingapparatus constructed in accordance with the present invention, andwhich in the illustrated instance is of substantially rectangular shape,and has open sides 2 and 3 normally closed by removable panels 4 and 5.Supported in insert parallel relation with the open sides of the casingis a partition 6 to provide a reeling and recording compartment I and acompartment 8 for containing driving and control mechanism.

Contained in the compartment I is mechanism for recording translatedsound waves in the form of magnetized points in a magnetic element, suchas a steel strand 9, having circular crosssection and which may have adiameter of .010 of an inch, the strand being stored upon a reel It anddrawn over a selective portion of the fleld of a magnet ii for rewindingupon a reel i2. The magnet il includes a laminated core it supportingspaced disks l4 and ll to form a spool on which a wire I I is wound andconnected in circuit with the respective sound translating or electricalcurrent translation apparatus (not shown) through connecting leads I!and II connected with suitable binding posts it and 20 carried onthe'face side of the partition. The core of the magnet includes aplurality of laminations H, 22, 24 and 24, the outer of which have theirends extending through openings in the disks and bent laterally as at 25to engage the outer faces thereof in securing the'assembly. The innerlaminations 22 and 24 terminate at one of their ends in upwardlyextending terminal portions to form jaws 28 and 21 between which amagnetizable point or pole piece 28 is anchored for influencing orscanning the wire as the case may be.

In devices of this character the fleld of the electromagnet has atendency to spread out and magnetize a larger area of the record thanthe portion in immediate contact with the pole tip. Because of thischaracteristic a greater area of wire or tape is ordinarily required toregister any individual cycle than would be necessary if the field wereconfined to an area approximating the thickness of the pole tip. Asimilar difllculty is encountered during the reproducing procedure fromthe stray flelds caused by the record itself. This is due to the factthat the lines of force or magnetic fields of the magnetized portion ofthe record do not extend at right angles from any magnetized point butinstead form curved paths which encompass a greater area than themagnetized point of the record. As a result of this condition thereproducing electromagnet is affected by a larger fleld area during thereproduction of any given cycle than the limited area of the magnetizedrecord required to record the cycle and distortion caused. Thiscondition is particularly disastrous to the higher frequencies inasmuchas each individual cycle must be registered within a very limited areathereby causing the stray flelds to combine and flatten the peaks of thewave forms. The reproduction is, therefore, not sharp and natural butthe sounds are somewhat muflied or flat. Such condition might be welllikened to a sound film system when the knife edge ray of light whichpasses through the sound track is allowed to get out of focus and spreadin such manner as to cause the light-sensitive cell to receive theblurred images of several wave forms at one time instead of the sharpimage of each separate wave as it should when the optical system is inproper adjustment.

The present invention, therefore, contemplates encasing the magnetwithin a shield of iron or other suitable magnetic material soconstructed that only the pole tip of the magnet element remainsunshielded for influencing or scanning the record as it is moved acrossthe guide.

In the illustrated instance the magnet is enclosed in a casing 29 formedof iron and having a cylindrical wall 20 closed at one end by anintegral end wall 3i and. at the other by a removable cover 32 alsoformed of iron or similar magnetizable material. The wall 20 is providedadjacent the open end thereof with a notch or recess 33 through whichthe terminal upper ends 75 34 and 26 of the jaws 26 and 21 project insupporting the magnet tip or pole piece 24. In order to better close thejoint between the cover 32 and the wall II, the cover is provided with asubstantially cylindrical boss 84 adapted to seat tightly within theinner open end of the wall 20 as clearly shown in Fig. 10, the boss 24being provided with a transverse groove 81 to accommodate the jaws 24and 21.

Threaded through an opening 38 in the lower portion of the wall 28 andextending through an opening 2! of a block 40 is a screw 4i adapted toengage a plate 42 which clamps the magnet against the opposite sideportion of the wall. The screw, after being adjusted, is retained fromrotation by a jam-nut 4i. The cover 32 is secured to the housing by ascrew 43 insertable through an opening in the cover and threaded into asocket 44 formed in the block 40.

The jaw 24 is provided with side flanges 45 and 48 to engage the sideedges of the magnet point 28 and prevent lateral shifting movementthereof. The jaw 21 is urged into gripping engagement with the magneticpoint by means of a set screw 41 threaded in an opening 48 in the coverand having i s inner end bearing against the jaw as clearly shown inFig. 8.

The magnetic point or pole piece 28 includes a relatively thin flatpiece of magnetizable metal having converging side edges 49 extendingupwardly above the jaws and through the notch 33 to terminate in aknife-like edge 50 for engaging the record. The portions of the jawsextending through the notch 33 are spaced from the adjacent parts of thecasing and cover 32 and the backing portion of the jaw 23 is preferablymagnetically insulated from the casing by a suitable insert M, as shownin Fig. 8, so as to prevent threading of the screw into the casing asufficient distance to crowd the jaw 26 into magnetic contact with thecasing as might be the case if the insulation were omitted.

In order to maintain the magnet in fixed relation with the record, themagnet is suspended from an arcuate shaped guide track 52 formed ofnon-magnetic material and having its ends supported by suitable brackets53 and 54 from the partition 8 as illustrated in Fig. 1, the magnetbeing suspended from the under side of the guide by an angle-shapedbracket 55 having one leg 56 fixed to the under side of the guide andits other leg 51 secured to the end wall Si by a screw 58 as shown inFigs. 1 and 8. The guide track is provided with an opening 58 inalignment with the notch 32 so that the magnetic point projectstherethrough into engagement with the record that travels through aV-shaped groove 60 formed in the upper face of the guide track as bestshown in Fig. 9. The V-shape of the groove is an important feature ofthe present invention, as it maintains the record in flxed definiterelation with the magnetic point of the magnet. Any vibration tendencyof the moving wire during passage across the magnetic point tends tointroduce background noises which when reproduced cause annoying hissingor fluttering sounds which may reach such proportions to exceed thevolume of the signals and cause suflicient distortion to render theapparatus impractical, but with the V-shaped groove and arcuate trackthe wire moves smoothly across the track, always centered within thebase of the groove to eliminate vibration tendency. This form of grooveis also important as it does not interfere with splices or repairs madein the wire in case of breakage since there is no chance for the splicesto become caught or jammed within the guide to cause further breakageand interrupt service of the machine.

The reel I0 storing the wire is mounted upon a shaft 8i rotatablycarried in a bearing 82 in the partition and in a bushing 63 carried ina bearing bracket 64 supported within the compartment 8. An end of theshaft projects into the compartment I for mounting a collar 65 that isfixed to the shaft by a set screw 66. The shaft projects from the collara sufllcient distance to provide support for the reel I0 and is fixed indriving relation with the reel by means of a pin 81 projecting from theface of the collar and engaging in an opening 88 extending through thereel as best illustrated in Fig. 3. The shaft is provided with a reducedthreaded portion 69 for mounting a thumb nut I0 to retain the reel. Abraking action is applied to the shaft to prevent free rotation of thereel. This is accomplished by providing a brake drum II mounted on theshaft between the partition and the bearing bracket 84 as bestillustrated in Fig. 3. The drum includes hub pcrtions I2 and 13, one ofwhich is provided with a set screw I4 adapted to engage against theshaft. The periphcry of the brake drum has spaced flanges I5 and 16 forguidingly retaining a brake band 'I'I in braking relation with the drum.One end of the brake band is anchored to, a stud I8 projecting inwardlyfrom the partition 8 while the other end extends over the face of thebrake drum and is secured to one end of a coil spring 19 having itsopposite end engaged with an anchoring bracket 00 fixed to the floor ofthe casing, The wire, upon being withdrawn from the reel, is guidedrelative to the track by extending it over a pulley 8i having aperipheral V-shaped groove for the wire. The pulley 8| is rotatablymounted on a stub shaft 82 carried in a bearing 83 on the partition 6.The wire is retained on the pulley by a block 84 bridging the groovetherein and which is supported on a rod 85 carried by an attachingflange 88 secured to the face of the partition 8, as best shown in Fig.l.

The winding reel I2 is fixed to its shaft 81 by a collar similar to thatdescribed in connection with the reel I0 so that driving of the shafteffects rotation of the reel to wind the wire thereon. The shaft 81 ismounted in a bearing in the partition and in a bushing 88 provided inthe bearing bracket 88 spaced from the partition and supported on thefloor of the casing, as best shown in Fig. 2. Rotatable on the shaftwithin the compartment 8 is a pulley 8i having a peripheral groove forreceiving a driving belt 82 operating over a drive pulley 93 on thearmature shaft of a motor 84 also. carried in the compartment 8, andhaving its base anchored to the floor of the casing. The pulley 9| isfrictionally driven by a plate 85 slidingly keyed upon the shaft andpressed against the side face of the pulley by a spring 98.

In order to wind the wire uniformly upon the reel I2 I provide a guidedevice 91 consisting of spaced arms 98 and 88 engaging the respectivesides of the strand at a point above the reel, the arms being attachedto a head I00 that is carried on a shaft IOI adapted to reciprocatethrough a bushing I02 in the partition. The shaft is reciprocated tomove the guide arm back and forth across the width of the reel by meansof a reciprocating mechanism now to be described.

Fixed on a side wall of the casing within the compartment 8 is a bracketI08 having laterally extending plate portions I04 and I05 providingsupport for parallel vertical shafts I08 and I01, the shaft I08 having aworm wheel I08 fixed to its lower end and meshing with a worm I08 fixedto the shaft 81. The upper end of the shaft I06 carries a pinion rearIIO meshing with a gear I I I fixed to the shaft I81. Fixed to the gearIII is a heart-shaped earn it! engageable with a depending pin I I8 onan arm I I4 that is pivotally mounted on a bracket II3 fixed to the wallof the casing at a point above the shaft IOI. The inner end of the shaftIOI is slotted to engage over the outer end of the arm I I and ispivotally connected thereto by a pin H6. The cam is located on the gearIII so that it reciprocates the shaft IOI to carry the guide arms backand forth across the width of the winding reel to effect winding of thestrand in smooth even lays across the width of the reel. The pin H8 isretained against the periphery of the cam by a coil spring having oneend anchored to the bushing I02 and its other end hooked to the shaftIOI as at III, so that the tension of the spring draws the pin intoconstant engagement with the edge of the cam.

If the wire were drawn across the magnet point by the winding force ofthe reel I0 any ineffectiveness of the guiding mechanism would cause thewire to pile up in slightly uneven layers, and theunevenness wouldgradually build up as additional wire is wound until a point is reachedwhere the guiding mechanism would become partially ineffective and themotion of the wire across the magnetic point would become jerky. Thiscondition would be aggravated when the record is being drawn from asupply reel upon which it had been unevenly wound. The effect of thisjerking movement of the wire is to cause not only a certain amount ofvibration in the moving wire as its tension is momentarily varied. butalso creates distortion during reproduction. I therefore provide adriving pulley II8 on the delivery side of the arcuate track having aV-shaped groove H9 about which the wire is completely looped beforethreading it between the guiding arms 88 and 99. A sufllcient contactarea of the wire is therefore provided with the pulley II8 so as toprevent slippage and the pulley H8 is driven at constant speed from themotor 94. by mounting the pulley on a driven shaft I20 that is rotatablymounted in a bearing in the partition and carries a driving pulley I22fixed to the end of the shaft that projects into the compartment 8, I

Operating over the pulley I22 is a drive belt I28 running over a secondpulley I24 fixed to the armature shaft of the motor alongside of thepulley 88 previously described. It is thus obvious that the pulley H8 ispositively driven to move the wire across the magnetic point or polepiece at constant speed so as to maintain uniform tension thereon andprevent any tendency for the wire to vibrate incidental to variabletractive forces acting thereon. It is also obvious that the wire ismoved at constant speed across the magnetic point regardless of anyvariation in take-up of the wire incidental to build-up of wire on thewinding reel. As the wire builds up on the winding reel the frictiondrive through the plate 88 permits sumcient slippage to compensate forthe increasing diameter of the coil of the wire.

When a record is being produced it is desirable to prevent contact ofthe portion of the wire moving onto the pulley from contacting theportion moving therefrom for the reason that the magnetism has notbecome fixed, and any contact of This is accomplished adjacent portionsof the magnetized wire will affect the recordings thereon, resulting incross talk or echo effects during reproduction. Therefore, at the time arecord is to be made, the wire passing fr m the pulley ,I I is threadedover an idler pulley I20 which is sufilciently out of line to preventany contact that would produce this effect. This action does not takeplace within the turns on reel I2 for the reason that the flux has hadsufficient time to drop to its minimum strength by the time a magnetizedsection of the wire reaches the reel, therefore no influence is impartedto the adjacent turns.

In making a record from a new wire, and particularly when it is desiredto make a second record on a used wire. I provide means for subjectingthe wire to a polarizing flux and to clear it of any previousmagnetization while a new record is being made. This is accomplished bya small permanent magnet I26 having substantially U-snape and supportedwith its pole pieces I21 and I28 directed over the guide track in thepath of the wire as it is moved across the magnetic point of theelectromagnet. In the present instance the pole I21 of the magnet isprovided with a laterally extending bar I29 that is pivotally mounted ina socket I30 carried by the partition 8, as best shown in Figs. 1 and 4.The pole faces of the magnet need not come into actual contact with therecord as it is only necessary to provide sufficient flux to cause thecorrect amount of polarization for the desired registration and therebyeliminate wear and noises as would result if the pole .pieces boreheavily on the wire.

The motor BI is preferably energized by means of a toggle switch I3Ithat is mounted on a bracket I32 and operated by a shaft I33 which isrotatably carried in bearing openings in the bracket and partitionrespectively. The shaft is rotated by a knob I34 and has a slotted crankarm I36 connectingly engaging the operating shaft I36 of the toggleswitch I. Wound on the shaft I33 is one end of a cable I31 having itsother end I38 connected with the spring I8. Thus when the switch isoperated to energize the motor sufficient cable is wound on the shaftI33 to release tension of the spring acting on the brake band andthereby release sufflcient braking pressure on the drum to allowrotation of the reel I0. However, sufficient tension is maintained bythe spring I8 to apply the required amount of braking force to preventfree unwinding of the reel.

In using an apparatus constructed and assembled as described for makinga record, the terminals I9 and 20 are connected with a suitableapparatus for translating sound vibrations to variable frequencies in anelectric circuit which then includes the terminals I0 and 20 so thatcurrent is passed through the coil of the magnet to energize the core I3and pole piece 23. The portion of the pole piece extending through thefield and opening in the arcuate guide sets up a limited and controlledfield in the path of a wire moving through the guide, the effectivefield being substantially only the width of the pole piece. The wire onwhich the record is to be made is wound on the reel I0 and the reelslipped on its shaft, after which the thumb nut is applied to secure thereel. The wire is then threaded between the block 84 and the groove ofthe pulley 8| across the arcuate guide, so that it seats in the bottomof the V-shaped groove thereof and then once around the groove of thepulley H0. The wire is then. passed between the may begin at any pointthroughout the length of the wire and then may be rewound and reproducedwithout disturbing previously made records which may be carried uponother sections of the wire.

Driving of the motor actuates the pulley H8 to draw the wire through thetrack and across the tip of the pole piece so that the fluctuatingcurrent in the coil sets up a corresponding field about the pole pieceto magnetize points in the wire.

I30 so that the poles I21 and I28 thereof are carried directly above thewire to polarize it and to neutralize any magnetic effects that occur inthe wire previous to passage of the wire across the tip of theelectromagnet. driven through the slip clutch connection with the pulleyat to take up the portion of the record wire on which the recordings aremade. The guide arms 08 and 88 are reciprocated back and The magnet I isinserted in a socket 20 The reel I2 is also forth across the width ofthe reel incidental to the cam and driving mechanism including the gearsI08, I09, H0 and III to wind the wire in uniform layers on the reel I2.After the record has been made the wire is rewound by interchanging theposition of the reels I0 and I2 on the shafts 8i and 81. The wire isthen caused to travel directly from reel I2 to reel I0 withoutsubjecting it to the control of the guiding nechanism which is notrequired during the rewinding procedure. wire taut and causes each ofthe turns to travel directly from its position on reel I2 to a relativepoint on reel I0 resulting in substantially smooth, even layers. Thewire actually guides itself back and forth across the reels as thevarious turns are rewound. Rewinding is accompl shed in a fraction ofthe time required for recording due to the fact that the wire is notsub- Jected to the controlling action of driving pulley H3, consequentlyno slippage occurs in the friction drive plate 05 and the motor drivesthe winding reel at maximum speed. The magnet I28 is then removed andthe wire bearing the magnetic record is threaded in the same manner asabove described, so that when the motor is set in operation the wirewill be drawn through the groove and across the tip of the pole piece.The terminals i0 and 20 are disconnected from the translating equipmentand connected with a sound amplifier wherein electric frequencies aretranslated to audible sounds. The passage of the magnetized points ofthe record across the tip of the pole piece sets up varying electricalimpulses in the electromagnet and these impulses in turn are amplifiedand converted into sound impulses by suitable translating equipment.Since the field of the magnetic tip is limited as above described. thereproduced sounds have the same quality as the s "nds previouslyrecorded.

From the foregmng it is obvious that I ha e provided a simple andrelatively inexpensive apparatus wherein sounds and signals may berecorded and reproduced on a strand-like record compared with theoriginal sounds, and that the The pull exerted by reel I0 keeps the 40limited field of the electromagnet tip influences only a limited area onthe record so that it is not necessary to move the record at excessivespeeds that result in extraneous noises usually resulting ir the presenttype recordings.

What I claim and desire to secure by Letters Patent is:

1. In an apparatus of the character described, in combination with amagnetic record element, an electromagnet including a pole piece havinga face portion, means for supporting the electro magnet with the faceportion of the pole piece in influencing relation with said recordelement. means for confining the effective field oi the pole piece tosaid face portion, and means for moving said record element relativelyto said face portion.

2. In an apparatus oi the character described, means for guiding amagnetic element for movement through a fixed path, an electromagnethaving a pole piece projecting into contacting relation with saidelement moved across said guide means, and shielding means for saidelectromagnet including said pole piece for limiting the effectivemagnetic field to the immediate locality of the contacting portion ofsaid pole piece.

3. In an apparatus 01' the character described, a guide having a groovefor guiding an elongated record member, an electromagnet having a polepiece projecting into contacting relation with said record member movedthrough said groove, and shielding means for said electromagnetincluding said pole piece for limiting the effective magnetic field tothe immediate locality oi the contacting portion of said pole piece.

4. In an apparatus of the character described, a guide having a groovefor guiding an elongated record member of the type described, anelectromagnet having a pole piece projecting into contacting relationwith said record member moved through said groove, shielding means forsaid electromagnet including said pole piece for limiting the effectivemagnetic field to the immediate locality of the contacting portion ofsaid pole piece, a traction member having a groove encircled by saidrecord member, and means for driving the traction member to draw therecord member through said guide groove.

5. In an apparatus of the character described, a guide having a V shapedgroove for guiding a continuous magnetic element, an electromagnethaving a pole piece projecting into contacting relation with saidelement moved through said groove, shielding means for saidelectromagnet including said pole piece for limiting the effectivemagnetic field to the immediate locality of the contacting portion 01'said pole piece, a traction member having a groove encircled by saidelement, and means for driving the traction memher to draw the magneticelement through said guide groove.

6. In an apparatus of the character described, a guide having a groovefor guiding a continuous magnetic metal record element, an electromagnethaving a pole piece projecting into contacting relation with saidelement moved through said groove, shielding means for saidelectromagnet including said pole piece for limiting the effectivemagnetic field to the immediate locality oi the contacting portion ofsaid pole piece, a traction member having a groove encircled by saidelement, means for driving the traction member to draw said elementthrough said guide groove, and means for maintaining substantiallyconstant tension on said element.

'7. In an apparatus oi the character described,

in combination with a magnetic record element, an electromagnetincluding a pole piece having a face portion, means for supporting theelectromagnet with the face portion of the pole piece in influencingrelation with said record element, means for confining the eiiectivefield of the pole piece to said face portion, means for moving saidrecord element relatively to said face portion, and means for polarizingand neutralizing magnetism in said element.

8. In an apparatus of the character described, a guide having a groovefor guiding a continuous magnetic metal record element, an electromagnethaving a pole piece projecting into contacting relation with saidelement moved through the groove, shielding means for said electromagnetincluding said pole piece for limiting the effective magnetic field tothe immediate locality of the contacting portion oi said pole piece, anda magnet supported above said guide at a point spaced from said contactpoint of the pole piece to polarize and neutralize magnetization in saidrecord element prior to contact thereof with said pole piece.

9. In an apparatus of the character described, a guide having a groovefor guiding a continuous magnetic element, an electromagnet having apole piece projecting into contacting relation with said element movedthrough the groove, shielding means for said electromagnet includingsaid pole piece for limiting the eflective magnetic field to theimmediate locality of the tip 0! said pole piece, and a magnet supportedin the field of said element at a point spaced irom said contact pointof the pole piece to polarize and neutralize magnetization in saidelement prior to contact thereof with said 'pole piece.

10. In an apparatus of the character described. a curved guide having aV shaped groove for guiding a magnetic metal record element, anelectromagnet having a pole piece projecting into contacting relationwith said element moved through the groove, and shielding means for saidelectromagnet including said pole piece for limiting the efiectivemagnetic field to the immediate locality of the contacting portion ofsaid pole piece.

11. In an apparatus 01' the character described, means for passing amagnetic metal strand through a fixed path, an electromagnet, meanssupporting the electromagnet with a selected portion of the field ofsaid electromagnet in the path of said strand, and means for shieldingthe remainder of said field from the said strand.

13. In an apparatus of the character described, means for passing amagnetic metal record element through a fixed path, an electromagnet,means supporting the electromagnet with a selected portion oi the fieldof said electromagnet in the path of said record element, means forshielding the remainder of said field from the said record element, andmeans for removing magnetism from said record element.

13. In an apparatus of the character described, an arcuate guide havinga V-shaped groove to form a track for guiding a magnetic metal strand,9. reel for storing the strand, a reel for winding the strand, means forapplying a braking force to the storage reel, means for rotating thewinding reel, a driving pulley having a groove for accommodating a loopin said strand to provide driving contact between the pulley and saidstrand, means supporting the pulley at the delivery end of the track,means for driving the pulley, means for adjusting lays oi the strand onthe winding reel, and means for supporting the adjusting meansintermediate the driving pulley and said winding reel.

14. In an apparatus of the character described, an electromagnetincluding a core, a winding on said core, means connected with the coreforming spaced jaws, a shield for said electromagnet having an openingin registry with said jaws, and a removable pole piece engaged betweensaid jaws and having a tip projecting through said opening to influencea magnetic metal record moved across said tip.

15. In an apparatus oi the character described. an electromagnetincluding a laminated core, a winding on said core, means forming spacedjaws on a pair of said laminations, a shield for said electromagnethaving an opening in registry with said jaws, and a removable pole pieceengaged between said jaws and having a tip projecting through saidopening to influence a magnetic metal record moved across said tip.

16. In an apparatus of the character described, an electromagnetincluding a laminated core, a winding on said core, means forming spacedjaws on a pair of said laminations, a shield for said electromagnethaving an opening in registry with said jaws, a removable pole pieceengaged between said jaws and having a tip projecting through saidopening to influence a magnetic metal strand moved across said tip, andthreaded means carried by the shield for effecting clamping engagementof said jaws to secure the pole piece.

1'7. In an apparatus of the character described, an electromagnetincluding a laminated core, a winding on said core, means forming spacedjaws on a pair of said laminations, a shield for said electromagnethaving an opening in registry with said jaws, a removable pole pieceengaged between said jaws and having a tip projecting through saidopening to influence a magnetic metal strand moved across said tip, andmeans supporting the electromagnet in said shield.

18. In an apparatus of the character described, an arcuate guide havinga V-shaped groove and provided with an opening, an electromagnetineluding a laminated core, a winding on said core, means forming spacedjaws on a pair of said laminations, a shield for said electromagnetsuspended below said guide and having an opening in registry with thejaws and guide opening, and a removable pole piece engaged between saidjaws and having a tip projecting through said registering openings toinfluence a metal strand moved across said tip and through the V-shapedgroove of the guide.

19. In an apparatus of the character described, an electromagnetincluding a core, a winding on said core, means connected with the coreforming spaced jaws, a shield for said electromagnet having an openingin registry with said jaws, a removable pole piece engaged between saidjaws and having a tip projecting through said opening, and means formoving a magnetic record across the tip of the pole piece to induce afluctuating magnetism in the pole piece for effecting a variableelectrical potential in said winding.

20. In an apparatus of the character described, an electromagnet casingforming an electromagnetic shield and having an opening, anelectromagnet enclosed in said casing and having a pole piece projectingthrough said opening whereby the efiective field oi. the electromagnetis confined to the portion of the pole piece projecting through saidopening, and mems for moving a magnetic element across said opening incontacting relation with the pole piece.

21. In an apparatus 0! the character described, an electromagnet casingforming an electromagnetic shield and having an opening, anelectromagnet enclosed in said casing and having a pole piece projectingthrough said opening whereby the effective field of the electromagnet isconfined to the portion of the pole piece projecting through saidopening, means for moving a magnetic element across said opening incontacting relation with the pole piece, and means for uniformlymagnetizing said moving magnetic element.

TOM J. MOLLOY.

